i have a pretty much an unused mpc500 i recently wanted to expand the ram so i got the required raminstalled the ram now every time i turn on the mpc it is stuck on the 'mpc500 startup' screen and is frozen

i've done the os reinstall from the cf card it installed the OS but same problemi take the ram out of the unit and it boots as normal to 16mb put the ram back in and it doesn't get past the mpc500 startup screen, I have the correct ram i also have tried the official akai brand red ram for this unit aswell and have had the same problems

Initialize To Factory Default Various Sample and Sequence settings can be saved to Compact Flash when the file is saved. The global settings found in the MPC500 (listed below) are saved to the internal Flash Memory and stored when the MPC500 is turned off. You can re-initialize the Factory Preset settings using the following procedure.

I am having the same issues right now. About a month ago upon bootup, my 500 went into RAM diagnostic mode also. It always makes it to Pass 4 50% and then gives me an error. I happen to have two other RAM sticks, get the same results.

The RAM slot is mounted to the bottom of the main board through surface mount technology from what I see. I doubt you can easily replace it, I don't believe I could. I have my doubts if that is the issue. I could be wrong on both counts.

My experience, and this is my second mpc500 that I have had issues with, is that the main board or some of the ic components on it become unstable over time - or there are bugs in the firmware/os that eventually manifest themselves - leading to issues. I have not tried the factory reset yet, but don't expect it to resolve my memory issue. Who knows, probably worth a shot. Like you, I might be limited to using it with 16 mb ...

I am having some issues in that mode with sounds cutting out when I build a sequence, which I believe is related to polyphony limitations and I assume the memory limitation of 16 mb. Probably need to look at what autoload is loading up ...

Don't mean to be negative Hopefully maybe someone with this issue in the past will speak up. I am going through old 500 posts, if I see something I will reference in this post.

I will also add:

In the absence of knowing what the issue is, most things cannot be ruled out ...

You cannot rule out that the ram that you purchased as not working. I cannot rule out the two additional ram sticks that I have as not working as I never tested them, just had them - bought them cheap - in case I needed them. It can certainly start to get expensive getting additional parts to test and try to eliminate causes.

In the case of my first mpc, the display does not work. I bought a $65 replacement lcd and it still does not work. Ouch. In this case, I believe I will live with the 16 mb ...

Are you guys using the AC power cord and not battery power when you boot up the MPC500? Could be low batteries.What about removing the CF card from the 500 while booting up? Still no changes to RAM issue?Are you using a PC 133 144PIN CL3 SODIMM 256MB RAM stick? Some forum members noted that you'll need the 256MB RAM stick in order to get the MPC500 to acknowledge just the max 128MB . I know... it sounds weird and thanks to Nukai for that dumb sh!t.https://www.mpc-forums.com/viewtopic.php?p=1586301#p1586301

fuzuku wrote: I was using a 12V 850mA adapter, and no way, it keep stuck in the main screen, like 80% of the time when I first started using it. Now it keeps stuck all the time with that adapter. I wouldn't recommend plugin it in to your MPC .

I stopped using that one, and switched to a 800mA adapter, same voltage, and no problem. Works perfectly.